Guiding vane for fans or the like



Feb. 4, 1936. R. DE MEY GUIDING VANE FOR FANS OR THE LIKE Filed 001;. 23, 1933 ENTDR R De. Me

Patented Feb. 4, 1 936 n, UNITED STATES PATENT OFFICE I 1 Application October 23, 1933, Serial No. 694,862

In France and Germany October 25, 1932 12 Claims.

The invention relates to fans or the like and concerns more particularly the design of the guiding vanes utilized in devices of this type, which may comprise one or more pressure stages.

The invention has for its chief object to provide guiding vanes such that more silent operation is obtained with, at the same time, all other things being equal, a greater ease of construction than heretofore.

It is known that the relative displacement at a high speed of lamellar elements or the like and a fluid is accompanied by sound phenomena.

This occurs in a particularly pronounced fashion when a rotor, such as the rotor of a fan, rotates relatively to a stator, such as the system of vanes with which a fan is provided, the pulsatory phenomenon being that which is utilized in the operation of syrens.

It is due to the pulsations of the fluid between the inlet edges of the guiding vanes and the rear edges of the screw blades in rotation.

In order to remedy this disadvantage, that is to say, to reduce the pulsation, it has already been proposed to give to the inlt edges of the guiding vanes a curved shape, the vanes being viewed both in profile and from the front.

If it is taken into consideration that the configuration of the edge of the vanes viewed in profile is determined by the shape of the rear edge of the associated screw blades, the reduction in the pulsations by this means is limited, the inlet edges of the vanes being necessarily rectilinear if the rear edge of the screw is of this form.

Viewed from the front, the configuration of the inlet edge of the guiding vanes is not limited, but as far as the applicant is aware, only a spiral configuration has been proposed heretofore.

With such a configuration, the inlet edges of the guiding blades approach both the base and the peripheral casing between which they are mounted, at relatively very small angles, thus creating at these points considerable resistance to the passage of the air, and thereby affecting the efii- ,ciency of the device in an appreciable manner.

The invention obviates these disadvantages.

To this end, it consists in giving to the inlet edge of the guiding vanes viewed from the front, a curved form such that it approaches and joins the peripheral line of the vaningthe peripheral region being that in which, all other things being equal, the least resistance to the passage of the fluid has the greatest importance by a portion reaching the said periphery at an angle The invention likewise consists in giving to the inlet edge of the guiding vanes viewed from the front a curved form such that it approaches and joins the base line of the vaning by a portion reaching the said base at an angle of incidence of high value.

Among the types and sections of curves capable of being utilized according to the invention, those will preferably be selected, in which the incidence (for instance relatively to a radius) is constantly modified between the base line and the peripheral line of the vaning.

Furthermore, while utilizing for the inlet edge of the vanes viewed from the front, curves and sections of curves as set forth hereinbefore, the invention consists in so disposing the said curves and sections of curves between the base line and peripheral line of the vaning that the portions joining them to the said base line and peripheral line are offset in the circumferential direction, that is to say, they do not lie on one and the same radius.

Finally, the invention consists in so disposing the inlet edges of the vanes that, in general direction, that they are inclined from the base to the periphery, in the direction of the advance of the associated blade.

In order to provide a good understanding as to how the foregoing dispositions may be carried into effect in practice, a description will be given hereinafter in greater detail of a preferred form of construction, shown by way of example in the accompanying drawing, wherein:

Figure l is a part front view of vaning constructed according to the invention.

Figure 2 is a profile view of the aggregate of a movable blade and a guiding vane.

In the figures, l denotes the axis of rotation, diagrammatically indicated by a point. 2, is the base line of the vaning and 3 is the peripheral line.

Between the said lines 2 and 3, the inlet edges g of the vanes 4 are developed along curves and portions of curves which approach and join the lines 2 and 3 by sections, the angles of incidence a: and y of which have high values (or the complementary angles of which have small values).

For example, as shownin the drawing, the angles a: and y will advantageously be in the vicinity of Of course, they may be difierent from or equal to one another.

Between thesections joining on to the base line and peripheral line, advantageously but not indispensably, however, the incidence of successive portions is modified, preferably constantly, as

may be observed for the portions a and c, the tangents 4 4 and c c of which intersect the radius 1-1at difierent angles.

In order to combine the high incidences of the junctions with the base line and peripheral line and the desirable conditions of a constant modification of incidence beiwveen the said junctions, while retaining an essentially continuous curvature, curves of sinusoidal shape, such as the curves g shown, will advantageously be employed.

As will also be seen in the figure, if the arrow denotes the direction of rotation of the screw blade 5 associated with the vane l, the curves 9' are inclined in this direction from the basetowards the periphery, this being favourable for the eificiency of the apparatus.

0n the other hand, the junctions with the base line 2 and the peripheral line 3, respectively, are offset circumferentially, that is to say they do not lie on one and the same radius, as may be observed for the radius 1-1 for example.

It follows that the fiuid meeting the inlet edges of the vanes will never be subjected to sudden variations in the circumferential direction.

Referring more particularly to Figure 2, it will be seen that the configuration of the inlet edge g of the vane 4 seen in profile is determined by the outlet edge 11 of the propelling screw blade with which it is associated and with which it is preferably parallel.

Whenever construction allows, it is expedient to give to the edge g viewed in profile acurved configuration in such a manner as to create a pressure difference only progressively in the axial direction from the base to the periphery or, what amounts to the same thing, so that the variations in pressure are produced in planes perpendicular to the axis of rotation which are different.

In the screw blade disposition according to the patent application No. 677,746 of the 26th June 1933, that is to say, essentially constructed with sections of wing or aerodynamic profile of 'constant geometric pitch, and in which the relative thickness, the relative curvature and the width are a, maximum in the section nearest the hub, the rear edge of the blade, seen in profile, is precisely of curved configuration, and it follows that the improved vane according to the invention will be preferably utilized with blades of this type.

I claim: v

1. A guide vane for fans or the like having an inlet edge as viewed from the front (that is to say in the direction of advance of the fluid along the axis of rotation) of curved form and inclined in the direction of rotation of the associated blade and said edge approaching and joining the peripheral line of the vaning by a portion reaching the said periphery at an angle of incidence of the order of 90.

2. A guide vane for fans or the like having an inlet edge of curved form and inclined in the direction of rotation of the associated blade and said edge approaching and joining the base line of the vaning by a portion reaching the said base at an angle of incidence of the order of 90.

3. A guide vane for fans or the like having an inlet edge of curved form and inclined in the direction of rotation of the associated blade and said edge approaching and joining the peripheral and base lines of the vaning by portions reaching the said periphery and base at angles of incidence of the order of 90.

4. A guide vane as claimed in claim 3, in which the angles of incidence are equal at the peripheral and base lines respectively.

5. A guide vane as claimed in claim 3, in which the angles of incidence are different at the peripheral and base lines respectively.

6. A guide vane for fans or the like in which the inlet edge has a double curvature, i. e. a sinusoidal shape, between the base and peripheral lines, reaching said lines at angles of the order of 90.

7. A guide vane for fans or the like having an inlet edge ofcurved form and said edge approaching and joining the peripheral line of the vaning by a portion reaching the said periphery at an angle of incidence of the order of 90 and the general direction of said edge being inclined to the peripheral line forwardly in the direction of movement.

8. A plurality of guide vanes for fans or the' like each having an inlet edge of curved form and said edge joining the base line at a point behind in the direction of movement relative to the joining point to the peripheral line of the inlet edge of the preceding vane.

9. A vane as claimed in claim 1 and in which the inlet edge is of curved configuration the vane being viewed in profile.

10. A vane as claimed in claim 2 and in which the inlet edge is of curved configuration the vane being viewed in profile.

11. A vane as claimed in claim 1 formed with successive aerofoil sections of constant geometric pitch, and decreasing width and increasing relative thickness and relative curvature in the successive sections from the periphery to the hub.

12. A vane as claimed in claim 2, formed with successive aerofoil sections of constant geometric pitch and decreasing width and increasing relative thickness and relative curvature in the successive sections from the periphery to the hub.

RENE DE MEY. 

